Kiara Aponte and Samir Husain loved their Tudor-style house in a leafy Houston suburb, with a brick fireplace and climbing roses. But beyond their property line, something was missing. There were sidewalks, but nobody walked on them. They identified neighbors not by name but by the car in the driveway. “There weren’t a whole lot of interactions, period,” Ms. Aponte said.

In 2024, two years after paying $280,000 and moving in, they left in search of better neighbors. They moved to Indigo, a new master-planned development about 30 miles from downtown Houston. Despite being in the suburbs, the development has a village feel, with a car-free parkway and strolling neighbors.

Developers of master-planned communities see fear of social isolation as a business opportunity. In California, the community of Silverwood asks residents to sign a kindness pledge. A development in Utah called Firefly markets its slow streets as an alternative to screen time. Indigo advertises homes in the low $300,000s with messages like “Know Your Neighbors.”

Ms. Aponte and Mr. Husain now live on Amity Lane in a duplex with a strip of grass for a backyard. They lost money on the old house and forfeited an ultralow interest rate for a high one. But Mr. Husain said it was worth it: “I don’t even ever think about the fact that I’m paying way more in mortgage. Because everything has been pleasant and happy.”